把“章节正文 + 图片”从 chapters 单表/JSON 结构，重构为“章节 chapter + 段落 section + 图片 memoir_images 独立表”的新数据模型，同时联动修改接口、PDF 导出、异步任务、迁移脚本、测试，以及修复 Android 端聊天列表显示问题。 (#9)

* refactor: 表结构重构，新增段落section和图片image新表

* fix: fix android app import error

* refactor: 重构文件名

* fix: 优化提示词

* fix: 消息气泡显示位置异常问题

---------

Co-authored-by: yangshilin <2157598560@qq.com>

api/tests/test_generate_chapter_images_task.py

@@ -9,6 +9,58 @@ from api.tasks import memoir_tasks
 from api.tasks.memoir_tasks import generate_chapter_images
 
 
+def _section_image_record(img_dict):
+    """把图片 dict 转成 image_record 用的 SimpleNamespace（可被任务更新属性）。"""
+    d = dict(img_dict or {})
+    return SimpleNamespace(
+        placeholder=d.get("placeholder"),
+        description=d.get("description"),
+        status=d.get("status"),
+        prompt=d.get("prompt"),
+        url=d.get("url"),
+        storage_key=d.get("storage_key"),
+        error=d.get("error"),
+        retryable=d.get("retryable"),
+    )
+
+
+def _chapter_with_sections(sections_data):
+    """构造带 sections 的 chapter stub，供 generate_chapter_images 使用（任务从 section.image_record 读/写）。"""
+    sections = []
+    for i, d in enumerate(sections_data):
+        img = d.get("image")
+        if img:
+            rec = _section_image_record(img)
+            sec = SimpleNamespace(
+                content=d.get("content", ""),
+                image_id="img-%s-%s" % (i, id(rec)),
+                image_record=rec,
+                order_index=d.get("order_index", i),
+            )
+        else:
+            sec = SimpleNamespace(
+                content=d.get("content", ""),
+                image_id=None,
+                image_record=None,
+                order_index=d.get("order_index", i),
+            )
+        sections.append(sec)
+    return SimpleNamespace(
+        id="chapter-1",
+        user_id="user-1",
+        title="童年的夏天",
+        category="childhood",
+        cover_image=None,
+        images=[],
+        sections=sections,
+    )
+
+
+def _bind_db_execute_to_chapter(db_mock, chapter):
+    """让 db.execute(select(...)).unique().scalar_one_or_none() 返回 chapter。"""
+    db_mock.execute.return_value.unique.return_value.scalar_one_or_none.return_value = chapter
+
+
 class GenerateChapterImagesTaskTest(unittest.TestCase):
     def setUp(self):
         memoir_tasks._REDIS_CLIENTS.clear()
@@ -26,29 +78,11 @@ class GenerateChapterImagesTaskTest(unittest.TestCase):
         session_local_cls,
         redis_from_url,
     ):
-        chapter = type(
-            "ChapterStub",
-            (),
-            {
-                "id": "chapter-1",
-                "user_id": "user-1",
-                "title": "童年的夏天",
-                "category": "childhood",
-                "content": "那条路我一直记得。",
-                "images": [
-                    {
-                        "index": 0,
-                        "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}",
-                        "description": "南方小镇的青石板路",
-                        "status": "pending",
-                        "url": None,
-                    }
-                ],
-            },
-        )()
-
+        chapter = _chapter_with_sections([
+            {"content": "那条路我一直记得。", "image": {"index": 0, "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}", "description": "南方小镇的青石板路", "status": "pending", "url": None}},
+        ])
         db = Mock()
-        db.get.return_value = chapter
+        _bind_db_execute_to_chapter(db, chapter)
         session_local_cls.return_value = db
         redis_from_url.return_value.set.return_value = False
 
@@ -74,29 +108,11 @@ class GenerateChapterImagesTaskTest(unittest.TestCase):
         storage_cls,
         session_local_cls,
     ):
-        chapter = type(
-            "ChapterStub",
-            (),
-            {
-                "id": "chapter-1",
-                "user_id": "user-1",
-                "title": "童年的夏天",
-                "category": "childhood",
-                "content": "那条路我一直记得。",
-                "images": [
-                    {
-                        "index": 0,
-                        "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}",
-                        "description": "南方小镇的青石板路",
-                        "status": "pending",
-                        "url": None,
-                    }
-                ],
-            },
-        )()
-
+        chapter = _chapter_with_sections([
+            {"content": "那条路我一直记得。", "image": {"index": 0, "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}", "description": "南方小镇的青石板路", "status": "pending", "url": None}},
+        ])
         db = Mock()
-        db.get.return_value = chapter
+        _bind_db_execute_to_chapter(db, chapter)
         session_local_cls.return_value = db
         prompt_service_cls.return_value.build_prompt.return_value = {
             "prompt": "A serene southern China town",
@@ -113,8 +129,8 @@ class GenerateChapterImagesTaskTest(unittest.TestCase):
             generate_chapter_images.run.__func__(task_self, "chapter-1")
 
         self.assertIs(ctx.exception, retry_error)
-        self.assertEqual(chapter.images[0]["status"], "failed")
-        self.assertEqual(chapter.images[0]["error"], "transient provider error")
+        self.assertEqual(chapter.sections[0].image_record.status, "failed")
+        self.assertEqual(chapter.sections[0].image_record.error, "transient provider error")
         task_self.retry.assert_called_once()
         storage_cls.from_env.return_value.upload_bytes.assert_not_called()
 
@@ -133,29 +149,11 @@ class GenerateChapterImagesTaskTest(unittest.TestCase):
         storage_cls,
         session_local_cls,
     ):
-        chapter = type(
-            "ChapterStub",
-            (),
-            {
-                "id": "chapter-1",
-                "user_id": "user-1",
-                "title": "童年的夏天",
-                "category": "childhood",
-                "content": "那条路我一直记得。\n\n{{{{IMAGE:南方小镇的青石板路}}}}",
-                "images": [
-                    {
-                        "index": 0,
-                        "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}",
-                        "description": "南方小镇的青石板路",
-                        "status": "pending",
-                        "url": None,
-                    }
-                ],
-            },
-        )()
-
+        chapter = _chapter_with_sections([
+            {"content": "那条路我一直记得。", "image": {"index": 0, "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}", "description": "南方小镇的青石板路", "status": "pending", "url": None}},
+        ])
         db = Mock()
-        db.get.return_value = chapter
+        _bind_db_execute_to_chapter(db, chapter)
         session_local_cls.return_value = db
         prompt_service_cls.return_value.build_prompt.return_value = {
             "prompt": "A serene southern China town",
@@ -176,10 +174,10 @@ class GenerateChapterImagesTaskTest(unittest.TestCase):
 
         generate_chapter_images.run("chapter-1")
 
-        self.assertEqual(chapter.images[0]["status"], "completed")
-        self.assertEqual(chapter.images[0]["storage_key"], "memoirs/user-1/chapter-1/0-7e1f860790.png")
-        self.assertEqual(chapter.images[0]["url"], "https://cos.example.com/memoirs/u1/c1/0.png")
-        self.assertEqual(chapter.images[0]["prompt"], "A serene southern China town")
+        self.assertEqual(chapter.sections[0].image_record.status, "completed")
+        self.assertEqual(chapter.sections[0].image_record.storage_key, "memoirs/user-1/chapter-1/0-7e1f860790.png")
+        self.assertEqual(chapter.sections[0].image_record.url, "https://cos.example.com/memoirs/u1/c1/0.png")
+        self.assertEqual(chapter.sections[0].image_record.prompt, "A serene southern China town")
         provider_inst.close.assert_called_once()
         db.commit.assert_called()
 
@@ -196,27 +194,9 @@ class GenerateChapterImagesTaskTest(unittest.TestCase):
         storage_cls,
         session_local_cls,
     ):
-        chapter = type(
-            "ChapterStub",
-            (),
-            {
-                "id": "chapter-1",
-                "user_id": "user-1",
-                "title": "童年的夏天",
-                "category": "childhood",
-                "content": "那条路我一直记得。",
-                "images": [
-                    {
-                        "index": 0,
-                        "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}",
-                        "description": "南方小镇的青石板路",
-                        "status": "pending",
-                        "url": None,
-                    }
-                ],
-            },
-        )()
-
+        chapter = _chapter_with_sections([
+            {"content": "那条路我一直记得。", "image": {"index": 0, "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}", "description": "南方小镇的青石板路", "status": "pending", "url": None}},
+        ])
         settings_from_env.return_value = SimpleNamespace(
             enabled=False,
             max_per_chapter=2,
@@ -227,15 +207,13 @@ class GenerateChapterImagesTaskTest(unittest.TestCase):
             max_attempts=20,
             liblib_template_uuid="tpl-uuid",
         )
-
         db = Mock()
-        db.get.return_value = chapter
+        _bind_db_execute_to_chapter(db, chapter)
         session_local_cls.return_value = db
 
         result = generate_chapter_images.run("chapter-1")
 
         self.assertEqual(result, {"status": "disabled"})
-        self.assertEqual(chapter.images, [])
         prompt_service_cls.assert_not_called()
         provider_cls.assert_not_called()
         storage_cls.from_env.return_value.upload_bytes.assert_not_called()
@@ -256,33 +234,15 @@ class GenerateChapterImagesTaskTest(unittest.TestCase):
         storage_cls,
         session_local_cls,
     ):
-        chapter = type(
-            "ChapterStub",
-            (),
-            {
-                "id": "chapter-1",
-                "user_id": "user-1",
-                "title": "童年的夏天",
-                "category": "childhood",
-                "content": "那条路我一直记得。\n\n{{{{IMAGE:南方小镇的青石板路}}}}",
-                "images": [
-                    {
-                        "index": 0,
-                        "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}",
-                        "description": "南方小镇的青石板路",
-                        "status": "pending",
-                        "url": None,
-                    }
-                ],
-            },
-        )()
-
+        chapter = _chapter_with_sections([
+            {"content": "那条路我一直记得。", "image": {"index": 0, "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}", "description": "南方小镇的青石板路", "status": "pending", "url": None}},
+        ])
         image_buffer = BytesIO()
         Image.new("RGB", (2, 1), color="white").save(image_buffer, format="JPEG")
         jpeg_bytes = image_buffer.getvalue()
 
         db = Mock()
-        db.get.return_value = chapter
+        _bind_db_execute_to_chapter(db, chapter)
         session_local_cls.return_value = db
         prompt_service_cls.return_value.build_prompt.return_value = {
             "prompt": "A serene southern China town",
@@ -320,33 +280,15 @@ class GenerateChapterImagesTaskTest(unittest.TestCase):
         storage_cls,
         session_local_cls,
     ):
-        chapter = type(
-            "ChapterStub",
-            (),
-            {
-                "id": "chapter-1",
-                "user_id": "user-1",
-                "title": "童年的夏天",
-                "category": "childhood",
-                "content": "那条路我一直记得。\n\n{{{{IMAGE:南方小镇的青石板路}}}}",
-                "images": [
-                    {
-                        "index": 0,
-                        "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}",
-                        "description": "南方小镇的青石板路",
-                        "status": "pending",
-                        "url": None,
-                    }
-                ],
-            },
-        )()
-
+        chapter = _chapter_with_sections([
+            {"content": "那条路我一直记得。", "image": {"index": 0, "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}", "description": "南方小镇的青石板路", "status": "pending", "url": None}},
+        ])
         image_buffer = BytesIO()
         Image.new("RGB", (1, 1), color="white").save(image_buffer, format="PNG")
         png_bytes = image_buffer.getvalue()
 
         db = Mock()
-        db.get.return_value = chapter
+        _bind_db_execute_to_chapter(db, chapter)
         session_local_cls.return_value = db
         prompt_service_cls.return_value.build_prompt.return_value = {
             "prompt": "A serene southern China town",
@@ -370,8 +312,8 @@ class GenerateChapterImagesTaskTest(unittest.TestCase):
             generate_chapter_images.run.__func__(task_self, "chapter-1")
 
         self.assertIn("AccessDenied", str(ctx.exception))
-        self.assertEqual(chapter.images[0]["status"], "failed")
-        self.assertIn("AccessDenied", chapter.images[0]["error"])
+        self.assertEqual(chapter.sections[0].image_record.status, "failed")
+        self.assertIn("AccessDenied", chapter.sections[0].image_record.error)
         task_self.retry.assert_not_called()
 
     @patch("api.tasks.memoir_tasks.SessionLocal")
@@ -389,29 +331,11 @@ class GenerateChapterImagesTaskTest(unittest.TestCase):
         storage_cls,
         session_local_cls,
     ):
-        chapter = type(
-            "ChapterStub",
-            (),
-            {
-                "id": "chapter-1",
-                "user_id": "user-1",
-                "title": "童年的夏天",
-                "category": "childhood",
-                "content": "那条路我一直记得。",
-                "images": [
-                    {
-                        "index": 0,
-                        "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}",
-                        "description": "南方小镇的青石板路",
-                        "status": "completed",
-                        "url": "https://cos.example.com/already-there.png",
-                    }
-                ],
-            },
-        )()
-
+        chapter = _chapter_with_sections([
+            {"content": "那条路我一直记得。", "image": {"index": 0, "placeholder": "{{{{IMAGE:南方小镇的青石板路}}}}", "description": "南方小镇的青石板路", "status": "completed", "url": "https://cos.example.com/already-there.png"}},
+        ])
         db = Mock()
-        db.get.return_value = chapter
+        _bind_db_execute_to_chapter(db, chapter)
         session_local_cls.return_value = db
 
         generate_chapter_images.run("chapter-1")